278257361 has 2 divisors, whose sum is σ = 278257362. Its totient is φ = 278257360.

The previous prime is 278257339. The next prime is 278257363. The reversal of 278257361 is 163752872.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 278255761 + 1600 = 16681^2 + 40^2 .

It is a cyclic number.

It is not a de Polignac number, because 278257361 - 2⁶ = 278257297 is a prime.

Together with 278257363, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (278257363) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 139128680 + 139128681.

It is an arithmetic number, because the mean of its divisors is an integer number (139128681).

Almost surely, 2^278257361 is an apocalyptic number.

It is an amenable number.

278257361 is a deficient number, since it is larger than the sum of its proper divisors (1).

278257361 is an equidigital number, since it uses as much as digits as its factorization.

278257361 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 141120, while the sum is 41.

The square root of 278257361 is about 16681.0479586865. The cubic root of 278257361 is about 652.8532252687.

The spelling of 278257361 in words is "two hundred seventy-eight million, two hundred fifty-seven thousand, three hundred sixty-one".